Thermo-electric air conditioner for automobiles



Feb. 7, 1967 G. H. sUDMEn-:R 3,302,414

THERMO-ELECTRIC AIR CONDITIONER FOR AUTOMOBILES Filed July 14, 1965 2'Sheets-Sheet l www@ fra/@ME45 Feb. 7, 1%? G. H. suomi-:IER 3,392,44

THERMO-ELECTRIC AIR CONDITIONER FOR AUTOMOBILES Filed July 14, 1965 2Sheets-Sheet 2 United States Patent O 3,302,414 THERMO-ELECTRIC AIRCONDITIGNER FOR AUTMBILES Gustav H. Sudmeier, 2708 Torrance Blvd.,Torrance, Calif. 90503 Filed July 14, 1965, Ser. No. 471,924 s claims.(ci. 62-3) The present invention .relates to a refrigeration system, andparticularly to van improved refrigeration structure that empl-oysthermo-electric cells to accomplish a tempera-ture differential, andwhich unit is well suited for automotive use.

In recent years, thermo-electric refrigeration systems have beendeveloped to accomplish a temperature differential directly from anelectrical current. One such system is shown :and described inco-pending application Serial Number 266,757, by the present inventor,which application will issue as Uni-ted States Patent No. 3,194,- 023,the subject matter of which is related to the structure hereof.

In general, prior systems employing thermo-electric techniques, haveincluded a plurality of short rods, made for example of bismuthtelluride, which rods are stacked in alignment between conductors so asto be energized by an electrical current. The electrical current thencauses a temperature differential across the rods that is sufficient foreither heating or cooling. Various structures employing thethermo-electric rods have generally had certain `attendantdisadvantages. Specifically, for example, it is important thatrefrigeration units of this type possess good insulationcharacteristics; however, with heating and cooling, the units undergosignificant physical deformation which is often difficult to accommodatein a well-insulated structure.

Another .aspect of structures employing thermo-electric rods is thedifficulty of providing the desired electrical connections to the rodsin an array. For example, it may be `desirable to connect the individualrods in a serial circuit; however, as the rods are physically disposedin par-allel between two plates, and as the plates have been formednormally of metal to provide good thermal conductivity, the rods havegener-ally been employed in a parallel electrical connection although inmany instances some serial connection may have been desired. In additionto these considerations, any technique which can improve the effectiveoperation of a thermo-electric unit represents a substantial advance inthe art.

Accordingly, it is an object of the present invention to provide animproved thermo-electric uni-t which is not subject to these and otherdisadvantages of prior structures.

Another object of the present invention is to provide an improvedthermo-electric unit which incorporates effective insulationcharacteristics and rugged mechanical support structure capable of,accommodating physical changes attendant temperature changes.

Still another object of the present invention is to provide an improvedmounting structure for thermo-electric rods, whereby they may beconnected in various parallel and .serial relationships, by employingmounting plates of heat-conductive ceramic, clad with conductivepatterns to accomplish the desired connections.

A further yobject of the present invention is to provide an improvedthermo-electric structure incorporating economical mounting for aplurality of thermo-electric cells, and incorporating structure todefine air-flow ducts through the structure.

One further object of the present invention is to provide an improvedsystem for lair conditioning an automobile by either warming or coolingthe interiorof the auto- 3,32,4l4 Patented Feb. 7, 1967 mobile throughuse of a thermo-electric structure particularly adapted for suchapplication.

Still one further object of the present invention is to provide animproved thermo-electric structure employing thermo-electric cells, andincorporating improved heatflow paths, whereby to obtain effectiveoperation in a va-riety of installations.

Briey, these and other objects and advantages of the present inventionare achieved in accordance with Ithe structural features of one exampleof the invention which includes a group of thermo-electric cells, eachof which comprises an array of thermo-electric rods mounted betweenplates of heat-conductive ceramic and interconnected by metallic foils;the cells then -being clamped between metallic plates which aresupported in -a charnber defined by elongate face opposing channelswhich are in turn enclosed within an insulating body.

Further details of the structure of the present invention as well asadditional objects and advantages thereof will become apparent and willbe best understood from a consideration of the following descriptiontaken in conjunction with the laccompanying drawings which are allpresented by way of illustrative example only; and in which:

FIGURE l is a diagrammatic representative of a system constructed inaccordance with the principles of the present invention;

FIGURE 2 is a sectional view of the temperature control unit of FIGUREl;

FIGURE 3 is a sectional view along the line 3-3 of FIGURE 4;

FIGURE 4 is a sectional view along the line 4 4 of FIGURE 3;

FIGURE 5 is a fragmentary View of a portion of the structure of FIGURE4; and

FIGURE 6 is a sectional View taken along line 6-6 of FIGURE 5.

Referring initially to FIGURE 1, the diagram discloses the elementalcomponent structure of an automotive air conditioning system. In thisregard, effective automotive air conditioning requires capability tocool as well as Iheat the interior of an automobile. Various systems forcooling and heating an automobile have come into widespread use;however, usually the systems include two distinctly separate structuresfor heating and cooling. Specifically, for example, the interior of anautomobile is typically heated by the engine coolant and cooled by acompressor refrigeration system driven by the engine. These dual systemsare usually complex and require substantial maintenance. Furthermore,many automobiles employ air-cooled engines, which are not well suited toprovide heat to the interior of the automobile.

In the system as shown in FIGURE l an automobile engine 10 drives analternator 12 lthrough a mechanical coupling indicated by a dashed line14. The alternator 12 then provides electrical energy through conductors16 to a battery l8r. As a result, the pulsating direct current output ofthe alternator 12 (as well known in the prior art) is transformed intosteady-state direct current output from the battery 18 which appears onconductors 20 and 22. The conductor 22 contains a manuallyoperatedswitch 26 and is connected -to a switch terminal 28, the conductor 22 isconnected directly to a switch terminal 30. Both the conductors 20 and22 are connected to blowers 32 which serve to transport air through atemperature control unit 34 as described in detail below. Thetemperature control unit 34 is connected to the movable terminals of areversing switch 36 which alternately engage the terminals 28 and 30depending upon the state of a relay coil 38. The relay coil 38 is inturn controlled by a thermostat 40.

In the operation of the system as shown in FIGURE l, closure of theswitch 26 initiates either a cooling or a heating operation by thetemperature control unit 34, depending upon the temperature sensed bythe thermostat 40 which in turn serves to control the coil 38.Specifically, if the thermostat 40 is set at a level below the actualtemperature, the relay coil 38 is unenergized and the switch 36 contactsthe terminals 28 and 30 in such a manner as to cause the temperaturecontrol unit 34 to provide cold air to the interior of the automobile asa result of the operation of the blowers 32. Conversely, if thethermostat 40 senses a temperature below the existing temperature, thecoil 38 reverses the switch 36 to oppositely engage the contacts 28 and30 resulting in an oppositely sensed current into the temperaturecontrol unit 34 which now provides hot air into the automobile, again bymeans of the blowers 32. Thus, the temperature control unit 34 mayalternately heat and cool the interior of an automobile depending uponautomatic setting of the switch 36 or alternatively by manual control isdesired.

Considering the detailed structure of the temperature control unit 34,reference will now be had to FIGURE 2 which shows a section of anautomobile body 44 defining ture control unit 34 is mounted forward of apanel 46 Y,

and supported on a platform bracket 48. Of course, a wide variety ofdifferent mounting arrangements and installation techniques may beemployed in placing the temperature control unit within an automobile;however, the arrangement as shown in FIGURE 2 has been found to operatesatisfactorily.

The temperature control unit 34 contains two distinct air flow passagesserving to stabilize the temperature of operation and to provide eitherwarm or cool air into the automobile, as desired. Specifically, apassage 50 through the temperature control unit 34 is connected to anintake duct 52 which is in turn connected to a blower 32a provided withan intake at a Vent 54. The exhaust of the passage 50 is connected to anexhaust duct 56 which is in turn connected to an exhaust vent 58.Therefore, ambient air outside the automobile body 44 is drawn into thevent 54 by the blower 32a, passed through the intake duct 52 and thepasage 50 to be exhausted through the exhaust duct 56 and the vent 58.As a result, undesired heat or cold is carried from the temperaturecontrol unit.

The desired heat or cold as the case may be, is provided inside the body44 by convection currents which flow through a passage 60 in thetemperature control unit 34. That is, a blower 32h forces air from theinterior of the body 44 through an intake duct 62 against a divider vane64, causing the air to flow through the sides 60a and 6017 of thepassage 60. The side 60a exhausts through a duct 68 while the side 60hexhausts through a duct 70.

At a time when the temperature control unit 34 is functioning to heatthe interior of the automobile body 44, air flowing through the passage60 is heated while air owing through the passage 50 is cooled.Conversely, during the operation of cooling the interior of theautomobile, air flowing through the passage 60 is cooled while airflowing through the passage 50 is heated. As indicated above, theselection of heating or cooling for the interior of the automobile, isdetermined by the sense of electrical currents which ow through theindividual thermo-electric cells contained between the passages 50 and60 as described in detail below.

The passages 50 and 60 are defined respectively by a pair of elongatechannels 72 and 74 (FIGUREl 3). The channels 72 and 74 may be formedlfrom a single extrusion, and incorporate a bottom section 76terminating in outwardly-extending sides 78 which carry lips 80 definingface opposing grooves 82 to receive a plate. Specifically, the groovesin the lips of the channel 72 receive a plate 86 which is integral withelongate fins 88 which extend into the passage 60 defined by the channel72. T he plate 86 along with the integral fins 88 may be formed of analuminum extrusion and the fins 88 may incorporate serrations 89 toafford greater radiating area.

The grooves 82 in the lips of the channel 76 receive a plate 90 havingan array of pin fins 92 extending outwardly therefrom into the passage50. The pin fins 92 are provided in an array of rows and columns;however, the rows and columns need not be regularly formed. In one formof the structure, the plate 90 has been formed of sheet copper, with thepin fins 92 spot welded thereto in the form of copper rods.

The plates 86 and 90 comprise a clamp held together by nylon studs 94that are threadably received in the plate 90. Of course, other forms ofinsulating material may be employed as the studs 94. The individualthermo-electric cells 96 are thus held clamped between the plates 86 and90 to which the radiating fins are attached so as to extend into thespaces defined by the channels 72 and 74. The integral unit is thusbound together as a flexible package and is covered by an insulatingbody 98 of light-weight foam material for example which may take theform of polyurethane. The exterior surface of the body 98 is then cladwith a skin 100 of aluminum foil or other material providing moreeffective insulation. Thus, the composite temperature control unit maybe formed to various lengths, and easily accommodate various numbers ofcells 96 depending upon each particular application. The spaced apartrelationship of the cells 96 within the unit accommodates physicaldistortion resulting from temperature changes and furthermore in thisregard, it is to be noted that the channels 72 and '74 having a crosssection that is generally U-shaped, are somewhat resilient, also toaccommodate distortion.

Considering the detailed structure of the cells 96, reference will nowbe had to FIGURES 5 and 6 showing individual rods 104 which are mountedin a regular array as shown. The rods 104 may be formed of bismuthtelluride, as well known in the prior art, and are electricallyconnected between conductors in the form of foil sheets 106 and 108. Thesheets 106 and 108 may comprise copper clad upon electrically insulatingplates and 112 respectively. These plates may comprise any of a varietyof heat-transmissive, electrically-insulating ceramic materials forexample, ceramic compositions comprising either aluminum oxide orberyllium oxide as a principal ingredient The sheets 106 and 108 arethen affixed to the interior surfaces of the plates 110 and 112respectively as by various techniques widely employed in theprinted-circuit arts. The arrangement of the conductive sheets 106 and10S may be made to accommodate any desired combination of serial andparallel circuits. For example, the rods 104 within a particular celland placed in a rectangular array, may all be connected in serialrelationship by staggering the pattern of the sheets 106 and 108 on theplates 110 and 112. Of course, other electrical circuit configurationsmay be accomplished as desired, simply by providing the requisitepatterns of connection.

The exterior surfaces of the plates 110 and 112 matingly engage theclamping plates 86 and 90. In this regard, the plate 112 is tinned orcoated with solder in an exterior coating 114 while the exterior surfaceof the plate 110 is coated with a heat-transmissive paste, e.g. siliconelgrease in a coating 116. The solder coating 114 on the plate 112 isthen fused to join that plate to the clamping plate 90. However, thepaste coating 116 on t-he plate 110 serves to mate the surfaces of thatplate with the plate 86 accomplishing good thermal conduction; howeverno physical connection, or at-tachment.

In the opertaion of the system, assume initially that it is desired t0Cool the interior of the automobile body 44 (FIGURE 2) by convectioncurrents passing through the passage 60. Thereupon, the manual switch 26(FIG- URE 1) is closed and the switch 36 is permitted to engage thecontact terminals 28 and 30 in the residual position, i.e. withoutmanual change or change by the coil 38. As a result, a current flowsfrom the battery 1S to the temperature cont-rol unit 34, andspecifically to the rods 104 (FIGURE 5) through the conductive sheets106 and 108. In one successful operating embodiment, the rods 104 areplaced in a serial circuit by the array of sheets 106 and 108, as fixedon the insulating plates 110 and 112. The sense of the direct currentthus passing through the ro-ds 104 is such that the plate 110 is cooledwhile the plate 112 is heated. That is, the junctions at the terminalsof the rods 104 are heated and cooled respectively so that the colddeveloped at the insulating plate 110 passes to the clamping plate 86and the fins 88. Convection air current-s propelled by the -blower 32k(FIG- URE 2) then ilow past the fins 88 to ow as cool air from the ducts68 and 70. As a result, the interior of the body 44 is effectively airconditioned by cool air.

In the event that it is desired to warm the interior of t-he body 44,the reversing switch 36 (FIGURE 1) is alternated to effectively reversethe sense or flow direction of current through the rods 104. This changeof direction has the effect of rendering the junctions which previouslywere cold, now hot and similarly changing the previously hot junctionsto cold junctions. T-hat is, the ends of the rods 104 abutting theconductive sheets 108 now become hot to in turn heat the plate 110 andthe plate 86 with the tins 88. As a result, the convection currents overthe tins 88 now warm the flowing-air currents and heat the interior ofthe automobile body 44. Thus, t-he temperature control unit 34 may serveeither as a heater or as a cooling air conditioner. As a result,considerable economy both in maintenance, space, installation expenses,and s-o on results from the combined temperature control unit havingdual capability.

A further important feature of the present invention resides in thestructure hereof which is sturdy but sufficiently resilient toaccommodate physical distortion resulting lfrom temperature changesattendant the operation of the unit. In this regard, it is alsoimportant to note that the unit is essentially of elongate structure andmay be somewhat cut or tailored to length depending upon any of avariety of custom installations. Further in relation to the ability ofthe system to accommodate individual applications, an important featureresides in the structure of the electrically-insulating,thermo-conductive ceramic plates which in cooperation with conductivefoil permit virtually any selected electrical circuit for the parallelrods. These as well as other features of the present invention areevi-dent from the embodiment described herein which represents merelyone exemplary form hereof. However, the scope of the invention is not tobe limited by the embodiment disclosed but rather shall be defined inaccordance with t-he following claims.

What is claimed is:

1. A thermo-electric temperature-control structure, comprising:

a plurality of thermo-electric cells for receiving electrical energy toproduce a temperature differential between a rst exterior surface and anopposed second exterior surface;

clamping means including a pair of parallel clamp plates to hold saidcells in clamped alignment with said exterior surfaces thereofcontiguous said interior surfaces of said parallel clamp plates;

a pair of elongate open channel means in faced relationship whereby todefine a space therebetween, said channel means each engageablyreceiving one of said clamp plates whereby to contain said cells andsaid clamping means wit-hin said space; and

an insulating body of resilient foam material laid with metal foilencircling said channel means to close said structure.

2. A thermo-electric temperature-control structure in accordance withclaim 1 wherein said cells comprise a plurality of thermo-electric rods;a pair of opposed holding plates of heat-conductive metallic ceramic forholding said rods aligned; and plural sheets of met-al foil disposed onan interior surface of each of said holding plates for electricalcontact to said rods whereby to provide a temperature differentialbetween a iirst exterior surface of one of said holding plates and asecond exterior surface of the other of said holding plates.

3. A thermo-electric temperature-control structure accor-ding to claim 2wherein said metallic ceramic comprises aluminum oxide as a principalingredient.

4. A thermo-elyectric temperature-control struct-ure according to claim2 wherein said metallic ceramic comprises beryllium oxide as a principalingredient.

5. A thermo-electric temperature control structure, comprising:

at least one thermo-electric cell including a plurality ofthermo-electric rods; a pair of -opposed holding plates ofheat-conductive metallic ceramic for holding said rods aligned; andplural sheets of metal foil disposed on an interior surface of each ofsaid holding plates for electrical contact to said rods whereby toprovide a temperat-ure differential between a first exterior surface ofone of said holding plates and a sec-ond exterior surface of the otherof said holding plates; said structure further comprising;

clamping means including a pair of parallel clamp plates to hold saidcells in clamped alignment with Said exterior surfaces thereofcontiguous said interior surfaces of said parallel clamp plates; and

heat exchange means affixed to each of said parallel clamp plates forstabilizing the temperature thereof.

References Cited by the Examiner UNITED STATES PATENTS 3,008,300 ll/1961Ryan 62-3 3,075,360 1/1963 Elfving 62-3 3,085,405 4/ 1963 Frantti 62-33,138,934 6/1964 Roane 62-3 WILLIAM 1. WYE, Primary Examiner.

1. A THERMO-ELECTRIC TEMPERATURE-CONTROL STRUCTURE, COMPRISING: APLURALITY OF THERMO-ELECTRIC CELLS FOR RECEIVING ELECTRICAL ENERGY TOPRODUCE A TEMPERATURE DIFFERENTIAL BETWEEN A FIRST EXTERIOR SURFACE ANDAN OPPOSED SECOND EXTERIOR SURFACE; CLAMPING MEANS INCLUDING A PAIR OFPARALLEL CLAMP PLATES TO HOLD SAID CELLS IN CLAMPED ALIGNMENT WITH SAIDEXTERIOR SURFACES THEREOF CONTIGUOUS SAID INTERIOR SURFACES OF SAIDPARALLEL CLAMP PLATES; A PAIR OF ELONGATE OPEN CHANNEL MEANS IN FACEDRELATIONSHIP WHEREBY TO DEFINE A SPACE THEREBETWEEN, SAID CHANNEL MEANSEACH ENGAGEABLY RECEIVING ONE OF SAID CLAMP PLATES WHEREBY TO CONTAINSAID CELLS AND SAID CLAMPING MEANS WITHIN SAID SPACE; AND AN INSULATINGBODY OF RESILIENT FOAM MATERIAL LAID WITH METAL FOIL ENCIRCLING SAIDCHANNEL MEANS TO CLOSE SAID STRUCTURE.